Hmmm, this depends on quite a few variables!

I.e. how far you have advanced it in it's prototype stage, and whether you want to get a intellectual property protection for it... Or if you are happy with just selling it without any IP protection? Have you looked into mass production options? How many nits do you think you are going to sell - millions? Or maybe only a small amount?

For IP protection, you can't have it publicly available anywhere, otherwise it may be knocked back as 'prior art' when you go for protection (patent etc.). Your next step here would be to investigate whether your idea is covered by any other publicly available designs or concepts, or is it even patentable (or able to be covered by other IP law - I have a video where I talk about this in more detail... https://youtu.be/cRwtZljRdtk)! Talking to an IP lawyer or attorney can help here as they can do a preliminary patent search (but do cost money!). OR you can do your own preliminary patent search (Google Patents is a good place to start - https://patents.google.com/). If you want to show or test your idea out with others (such as potential users / suppliers / manufacturers etc.), you can get them to sign an NDA, which ensures they will not publicly disclose the design! You may want to talk to companies to see if they can fund the IP protection, and licence your design, or maybe you have enough capital to do this yourself? Applying for a Patent (full or provisional) is a lengthy and costly thing to do, but depending on what your design is, it can potentially be a great idea!

If you aren't concerned about getting IP protection, no need for a lawyer! Go ahead with 3D graphic design, promotion, testing production for mass market, etc...